Class III chitinase expression and salicylic acid accumulation in chestnut after challenge with hypovirulent and virulent Cryphonectria parasitica (Murr.) Barr : 3rd EUROSILVA Workshop, Obergurgl, Austria, September, 10-14, 1998
The expression of homologous sequences to tobacco acid and basic class III chitinases (chi-a and chi-b respectively) and the accumulation of endogenous salicylic acid (SA) was investigated in stems of chestnut plants (Castanea sativa Mill.) grown in vitro after inoculation with the causal agent of chestnut blight, virulent (v) Cryphonectria parasitica, and with a biocontrol strain against chestnut blight, hypovirulent (hv) Cryphonectria parasitica. Wounded plants were used as a control. On day three after treatment, only in stems of wounded plants chi-a transcription was found to be stimulated. Neither chi-b expression nor SA levels were altered significantly three days after fungal treatment. But on day seven after infection, hypovirulent Cryphonectria parasitica treated plants exhibited clearly elevated levels of SA and the expression of chi-a and chi-b was strongly induced by hypovirulent Cryphonectria parasitica compared to plants inoculated with virulent Cryphonectria parasitica or wounded control plants. This shows that hypovirulent Cryphonectria parasitica stimulates defence mechanisms of the host stronger than the virulent strain.
